{smcl} {* 24mar2002}{...} {hline} help for {hi:xtsumcorr} {hline} {title:Summarize xt data} {p 8 14}{cmd:xtsumcorr} [{it:varlist}] [{cmd:if} {it:exp}] [{cmd:,} {cmd:i(}{it:varname}{cmd:)} ] {p}{cmd:by} {it:...} {cmd::} may be used with {cmd:xtsumcorr}; see help {help by}. {title:Description} {p}If you have not read help for {help xtsum}, please do so now. {p}{cmd:xtsumcorr} is an augmented version of {cmd:xtsum} that computes corrected version of within-panel and between-panel standard deviations. {p} The within-panel standard deviation is the same as that in {cmd:xtsum}, except that the divisor is (N - sum T_i) instead of (N - 1), where N is the total sample size and T_i is the within-panel sample size. This estimator is unbiased for the within-panel variance and is analagous to that reported in {cmd:xtreg , fe}. The between-panel standard deviation is computed as the square root of the overall variance minus the within-panel variance. {title:Example} {inp:. iis patid} {inp:. xtsumcorr bp} {title:Also see} Manual: {hi:[R] xtsum} {p 0 19}On-line: help for {help xtsum}, {help xt}{p_end}